Simple ODB2 Microcontroller Project, need some help.

**fab26x** · 10-18-2009, 11:14 AM

Hello guys,

I have a project using the ODB2 port and a microcontroller I'm going to start working on and would love some help. The project is pretty simple, the only information it needs to get from the car is real time RPM, throttle position, and MAP sensor. Once I have that information the microcontroller has to turn on or off an electric actuator. Thus, I'm planning to use some kind of programmable microconntroller board. Prob, a development board using something like a PIC18. chip.

What would be great is, a dev. board with an LCD to view a menu. Then control and adjust the commands.

Any help would be very thankful, I don't have a lot of cash, but would be willing to pay someone for their help.

Thanks,

Fabio

**michbound** · 10-19-2009, 08:21 AM

The simplest option would be to use an ELM327 type micro that does all the OBD2 stuff for you and then integrate it with your Dev board to display data etc.

Elektor has a number of articles on how to do this using a different chip but the concept is the same

http://www.elektor-electronics.co.uk...er.58218.lynkx

Thanks
Paul
OBDPros Scantool

**Curiosity** · 10-19-2009, 11:09 AM

Electric cutouts?

**fab26x** · 10-19-2009, 11:52 AM

Thank you Paul, For sure I will do some reading about that link. Now, if I just want to get the information from the car such as PRM's, MAP sensor and Throttle Position, do I need the ELM327 ? Or can I just use a programmable chip ?

Thanks,

Fabio

**Vitaliy** · 10-19-2009, 02:29 PM

Originally Posted by fab26x

Hello guys,

I have a project using the ODB2 port and a microcontroller I'm going to start working on and would love some help. The project is pretty simple, the only information it needs to get from the car is real time RPM, throttle position, and MAP sensor. Once I have that information the microcontroller has to turn on or off an electric actuator. Thus, I'm planning to use some kind of programmable microconntroller board. Prob, a development board using something like a PIC18. chip.

What would be great is, a dev. board with an LCD to view a menu. Then control and adjust the commands.

Any help would be very thankful, I don't have a lot of cash, but would be willing to pay someone for their help.

Thanks,

Fabio

Fabio, have you had a chance to look at Microchip's development boards? I personally prefer the 16-bit parts (33F or 24H), you get a lot more bang for the buck (easier to develop on, too).

You can start with an ELM327, or -- if you have some time -- we have an easy to use OBD module called microOBD in the works.

Best regards,

Vitaliy

**Curiosity** · 10-19-2009, 02:42 PM

Originally Posted by Vitaliy

Fabio, have you had a chance to look at Microchip's development boards? I personally prefer the 16-bit parts (33F or 24H), you get a lot more bang for the buck (easier to develop on, too).

You can start with an ELM327, or -- if you have some time -- we have an easy to use OBD module called microOBD in the works.

Best regards,

Vitaliy

Nice! That adds all the extra support circuitry needed for the ELM327 to talk to the car and has to be added on anyway. Plug-n-play.

**Superduck** · 10-20-2009, 10:56 PM

Not sure if it'd add way more complexity, or if it'd be better for saving some money, but if all you need is RPM, TPS and MAP, couldn't you just tap into the various sensors and use just any old I/O chip? 18F2455 or an Arduino or something? Or just grab an MSD Boost Control or Nitrous Control or something? I'm guessing you're using it for one of those two things? /shrug

Or I could be way off, and this is the start of something much cooler. Not that it wouldn't be cool regardless, I'm sure. I'll just shut up now.

Anyway, just my two cents after tax.

Cheers,

Kris

**fanl** · 10-21-2009, 02:07 PM

I am having hard time with ELM237, here in Brazil, I still couldn't find a fully OBD-II compliant car... None have awnsered proppely for the $01 PID 05 request.

**Vitaliy** · 10-23-2009, 09:00 PM

Originally Posted by fanl

I am having hard time with ELM237, here in Brazil, I still couldn't find a fully OBD-II compliant car... None have awnsered proppely for the $01 PID 05 request.

Your best be is to test it on newer cars, because Brazil only recently adopted OBD (there's even a choice for PID $1C now, "Brazilian OBD"). Or it could be that your ELM327 is bad.

Vitaliy